Haemophilus influenzae Type b Conjugate Vaccines: Immunization of Children at 15 Months of Age

Abstract

This statement updates previous information and recommendations regarding Haemophilus influenzae type b conjugate vaccines. The four vaccines that have received extensive clinical investigation and/or licensure by the United States Food and Drug Administration (FDA) are listed in the Table. Previously, the Committee recommended that all infants be immunized at 18 months of age with one of the two conjugate vaccines, designated PRP-D and HbOC, that were licensed at that time.1, 2 A third conjugate vaccine, designated PRP-OMP and consisting of the capsular polysaccharide of H influenzae type b complexed with outer membrane proteins of Neisseria meningitidis, was licensed by the FDA in December 1989. Currently, the FDA has approved labeling for PRP-OMP, HbOC, and PRP-D vaccines that states "Administration of Haemophilus b Conjugate Vaccine may be considered for children as young as 15 months of age when it is expected that the child will not return at 18 months for Haemophilus b immunization." After review of the data available on immunogenicity for PRP-D, HbOC, and PRP-OMP administered to children at 15 months of age, the Committee concludes that all children should be immunized at 15 months of age. BACKGROUND Before the introduction of immunization against H influenzae type b, it was estimated that annually approximately 16 000 cases of invasive infection occurred in the United States in children 5 years of age or younger.3 About 26.6% of cases occurred in children 18 months of age or older, and approximately an additional 9.3% occurred in children 15 to 17 months of age.